Throttle data files synchronization to 20 KiB/s
Throttle data files synchronization to 20 KiB/s

This is to avoid causing a bandwidth consumption spike which may trigger
additional throttling interference or affect other nodes participating in a
mesh VPN.  The limit still allows downloading more than 10 MiB in 10 minutes.

The first run will be the most affected, while following ones should not
because they will consist mainly of differential RSync updates.

equalitie/ceno2-testbed,equalitie/ceno2-testbed,equalitie/ceno2-testbed